1. Field of the Invention
The present invention relates to a coolant air bleed structure for a water-cooled internal combustion engine and to an engine incorporating same. More particularly, the present invention relates to disposition of a coolant air bleed structure in a water-cooled internal combustion engine having a plurality of cylinders.
2. Description of the Background Art
A number of coolant air bleed structures for an internal combustion engine, including disposition thereof in the engine, are known. An example of disposition of coolant air breed structure in a water-cooled internal combustion engine is disclosed in the Japanese Utility Model Laid-open No. Hei 1-160119.
According to the Japanese Utility Model Laid-open No. Hei 1-160119, the coolant air bleed structure includes an air bleed member disposed in a coolant pipe situated in a top (upper) portion of an engine cylinder head; and the engine coolant system is bled of air using the air bleed member disposed at the top portion of the cylinder head.
When the water-cooled internal combustion engine includes the coolant air bleed structure as described in the Japanese Utility Model Laid-open No. Hei 1-160119, it is necessary to loosen (or screw out) a bolt of the air bleed member to allow air bleeding from the cooling system during the coolant changing (replacing) operation. Such loosening of the bolt of the air bleed member during routine maintenance of the engine, i.e., replacing/flushing of the coolant disadvantageously requires more time and results in poor serviceability of the engine.
Moreover, the air bleed member of the Japanese Utility Model Laid-open No. Hei 1-160119, is disposed at a top (upper) portion, e.g., crown portion of the cylinder head. In other words, according to the Japanese Utility Model Laid-open No. Hei 1-160119, the air bleed member is not disposed in the sidewalls of the cylinder head. Such disposition of the air bleed member at the upper (crown) portion of the cylinder head does not allow building the engine compactly vertically, and also results in poor appearance of an engine body.
The present invention has been made to address the foregoing problems. Accordingly, it is an object of the present invention to provide a coolant air bleed structure for a water-cooled internal combustion engine which offers good serviceability, enhances compactness of the engine body, and improves appearance thereof.